Introduction of methyl groups on vinylene segments of phenylene vinylene systems: synthesis and properties?

Organic & Biomolecular Chemistry Pub Date: 2009-08-05 DOI: 10.1039/B909500D

Abstract

A facile synthetic route towards phenylene vinylene systems with methyl substituents at the vinyl linkages is demonstrated through palladium catalyzed Heck coupling of 1,4-diisopropenylbenzene with aryl bromides. The coupling leads to a series of model compounds that feature, in some cases, direct access to a trans-configuration at the double bonds. The oxidative stability of these systems is surprisingly unaffected by the presence of allylic C-H bonds in the methyl substituents. The methyl substituents modulate the electronic properties of the phenylene vinylene systems by inducing a significant twist to the conjugated backbone. The study suggests that the introduction of methyl groups at vinylene sites is a viable alternative to functionalising and tuning the properties of phenylene vinylene systems.

Graphical abstract: Introduction of methyl groups on vinylene segments of phenylene vinylene systems: synthesis and properties
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